


Leg Day

by Mustangwill



Series: Kinktober, 2019 [4]
Category: SpongeBob SquarePants (Cartoon)
Genre: Alternate Universe - Human, Body Worship, F/M, Gym Sex, Gyms, Muscles, Shower Sex, Size Difference
Language: English
Status: Completed
Published: 2019-10-07
Updated: 2019-10-07
Packaged: 2020-11-27 05:16:33
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,561
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20942873
Author URL: https://archiveofourown.org/users/Mustangwill/pseuds/Mustangwill
Summary: Fourth entry in my contributions to Kinktober 2019.Sandy Cheeks recently joined a new gym and has taken a shine to one of the regulars that always seems to be therewhen she goes. When she is approached by him, she finds out her initial feelings are reciprocated and they decide to set up a date. But what happens when Sandy is too impatient to wait for their date to see him?





	Leg Day

**Author's Note:**

> They are NOT in their aquatic, cartoon forms- this is a human form AU fic!

Sandy stepped out of the ladies’ changing room and began placing her ear buds in as she scanned the gym, her eyes almost immediately zeroing in on the large, muscular red haired man doing deadlifts in the back with his two, equally muscle bound friends cheering him on. At this late hour there were only a handful of other gym rats working out, which was just perfect for her because she could easily see him from anywhere in the building.

Why don’t you just go over and talk to him, you scaredy cat? Sandy thought to herself, her inner voice sounding much more like the strong, independent woman she had always thought she was, What’s the worst that could happen?

Because… she began making her way towards the treadmills stationed at the front of the gym, grabbing one of the bottles of complimentary water from the front desk as she went, trying to come up with a plausible excuse, because… he’s with his friends, and they look like they are in the middle of a serious workout anyways…

There was silence in her head as Sandy pulled out her workout iPod from the pocket of her workout shorts and selected her Wednesday night playlist- which was full of fast paced dance songs and sugary Top Forty songs to get her through her leg day workout- and that inner voice didn’t speak again until she was already a couple of songs in and was working up a light film of sweat. He’s wearing those shorts again that you like, it whispered, just loud enough for her to hear over the music. 

Her eyes left the bank of TV monitors hanging down in front of the treadmills- she really wasn’t even interested in the rerun of the nighttime talk show going on anyways- and looked once more towards the back of the gym where he was. The red haired man, who she had found out recently from a gym employee that his name was Larry, was spotting one of his friends bench pressing a large amount of weight. Larry could do more, her inner voice bragged and Sandy found herself nodding along smugly in agreement. Neither of his friends had muscles as large or as defined as Larry’s.

As she watched, the friend began to struggle with the last of his reps she could hear Larry shouting encouragement over her music, “Come on, Frank, just three more! Push it, just two more! You got it, bro, one more big push! Woo!”

Sandy smiled as Larry helped Frank rack his weights and all three began to whoop and chest bump one another in celebration. All three men were shirtless, their ripped chests, swollen biceps, and washboard abs glistening in the fluorescent lighting. All those rippling muscles… Her mouth suddenly felt as dry as a desert, she snatched up her complimentary water bottle and guzzled down half of it in one big gulp. When it didn’t seem to have had an effect, she upended the bottle on herself, gasping as the chilled water splashed over her heated skin.

I bet he could quench your thirst, her inner voice teased.

“Shove it,” Sandy growled under her breath and placed her empty bottle back into its cup holder. She need to refocus onto her workout or she would never get it finished.

“Did you say something?”

Sandy stumbled and cried out in surprise as she lost her footing, shooting backwards on the treadmill, only to be caught by what felt like iron bars. She was snatching her earbuds out of her ears to give an earful to whoever it was who had spoke when she looked up and froze, startled to see Larry holding her up! “Whoa, I didn’t mean to startle you there; you all right?” he asked as she just stared up at him, her mouth gaping open. He chuckled and helped her to a more upright position, “Cat got your tongue?” 

Sandy laughed awkwardly and quickly stuffed her ear buds into her shorts pocket, “No, umm… hehe, thanks for catching me and all… could have been bad…” She could feel her cheeks burning as she stood there before the giant of a man, looking very tiny in comparison. He had to be six foot four, a good hundred more pounds of muscle on her, and the sweaty, musky scent wafting off him had her swooning. Quickly scrambling to get the more lewd thoughts from creeping their way to the forefront of her mind, she jerked her thumb back towards where he had just been working out, “You finishing up your sets already?”

“Yep, just came up here for a drink before heading back for a quick shower,” Larry explained, gesturing towards the front desk, “would you like to get a ‘drink’ with me?”

He had such a cheesy smile at his joke that Sandy couldn’t help but laugh and agree to have a ‘drink’ with him. They spent such a long time talking that the gym was practically empty by the time they finished, with just them and a single gym employee cleaning up the machines as busy work, but she was able to learn a lot about him in that time. He was passionate about healthy living and bodybuilding- both hobbies she had been able to guess on her own- but she was also able to find out he was a licensed lifeguard and that he liked to do extreme sports with his friends. He was smart, at least enough to understand she was a marine biologist and the studies she was currently doing on undersea life, and she liked all his corny little jokes.

“So, a marine biologist AND a black belt in karate?” Larry asked, finishing off his second water bottle and tossing it into a nearby recycling bin, “How do you do it all?”

Sandy tossed her two bottles into the recycling bin as well before smiling up at him, “Well, I could ask you the same thing; you have way more on your plate than I do.”

“Well, when you’re passionate about something, you find the time,” he gave her a suave smile and leaned on the front desk, “speaking of which, what are you doing on Friday night?”

Sandy could feel her cheeks burning again and she stammered, “I- I’m not doing anything F-Friday night.” See?! All you had to do was talk to him! her inner self cried out in triumph.

“Great!” Larry smiled and stood up, moving towards the men’s locker room, “I’ll meet you here at six Friday night; I know a really great Japanese sushi place downtown that you’re going to love. I’ll see you then.”

“See you then,” she echoed and, as soon as he was out of sight, she did a victory dance as both she and her inner self squealed in delight. Feeling a boost of energy from the giddiness, she fished her ear buds back out of her pocket and headed towards the leg weight machines, sporting a bright smile. She had just sat down and was adjusting the weights when her inner voice reared its head, whispering to her over the music, You know… you don’t have to wait until Friday to see him again…

And, the next thing she knew, she was standing outside the men’s locker room, watching until the gym employee had their back to her before she slipped inside. She felt a strange calmness overtake her, which was weird because she knew she could get into a lot of trouble if she were to be caught. Something was telling her that she wouldn’t though, and that everything was going to be okay.

She could hear a shower running further in the back of the locker room- she could even make out wisps of steam floating past the open doorway at the opposite end of the room. Making her way towards it, she began to strip off her clothing one piece at a time, leaving a trail of athletic attire in her wake until she stood naked in the doorway, peeking inside.

To her left, she could see several sinks and mirrors with benches in the center for men to set down their bags or sit themselves down to change. To her right were the showers, eight in total- three on each side and two larger handicap showers set in the far wall- which she could tell Larry was in the last stall on the left, the steam rising up to the ceiling there.

“Need someone to wash your back?” she asked seductively as she pulled aside the flimsy stall curtain, taking up a pose she had seen a swimsuit model on the cover of a magazine she had seen once.

Larry jumped, dropping the bottle of body wash he had been picking up and spun to look at her in stunned shock, “S-Sandy? What are you-”

“Shh,” she whispered, placing her finger against his lip, placing the bottle of body wash in his hand, “I just couldn’t wait until Friday to see you again.” Stepping into the stall, she drew the curtain back closed behind her and pressed herself up against him, her hands moving to rest on his muscled pectorals. 

Seeming to recover quickly from his initial surprise, his usual suave confidence returned and, setting aside the body wash, his hands moved to rest on her hips, pulling her even closer until their bodies were plastered against one another, “I don’t mind being impatient.”

And then he was kissing her, and she felt as if her world had fallen away beneath her, the only thing tethering her was his hands on her. Her body began to radiate heat as her desire for this man seemed to roar into a searing fire. Their hands were all over one another, their tongues wrestling for dominance as Sandy maneuvered him to step back until they were both under the water spray. When they parted to take a much needed breath, she took the opportunity to run her hands over his body, feeling her body ache at the hard, sinewy muscles just under the skin.

“You feel so good,” she groaned, her fingers tracing a vein down his bicep as a primal urge began to take over her senses, “good enough to bite.”

“Well, I do work out every- mmm!” Larry began, flexing the impressive bicep when he was interrupted by a groan of desire as Sandy leaned in and lightly bit the bulging muscle, “Careful… you don't want to chip a tooth.” He turned his arm to allow a less awkward position for her as she began to nibble along his arm toward his shoulder, letting out little moans of delight and squirming as her body weeped with desire for him to touch her. 

Which he was only too happy to oblige. His large hand slid down her toned back, leaving shivers and goosebumps in its wake, to palm one ass cheek. “Mmm, nice and firm,” he groaned in appreciation as he gave it a firm squeeze, and repeated the process with its twin, “yes, you’ve done quite nicely here.”

“Never miss leg day,” Sandy repeated the mantra her high school fitness coach had drilled into her. Reaching his shoulder, she worked her way along his collarbone, leaving little red marks along his perfect tanned skin as she went, “A good foundation is key.”

“I couldn’t agree more,” he groaned as he slid his free hand down her back to cup both her ass cheeks and, gripping her tightly, he lifted her up until she was forced to wrap her legs around his waist or risk falling back down. 

“Mmm, strong boy,” she purred, wrapping her arms around his neck and ground herself against the hard erection trapped between them, “I’ve been wanting to touch these beautiful muscles ever since the first time I saw you.” 

“Feel free to touch them to your heart’s content,” he groaned, softly biting along her neck and shoulder, “just remember if you break them, you buy them.”

Laughing, Sandy grabbed a fistful of his flaming red hair and pulled his head back until he was forced to look at her. She kissed him hard and, when they parted, she stared into his dazed eyes and growled, “I want you to fuck me as hard as you can.” 

He didn’t need any further encouragement. Turning clockwise, he pushed her up against the tile wall, making her gasp and arch her back as she came in contact with the icy cold tiles. Her breath hitched and her nails sank into his back as his hard erection was readjusted and he slid himself up into her.

His hands on her hips tightened as her slick heat enveloped him, squeezing him as he thrust himself fully inside her until he was pressed firmly against her cervix, “So hot…” Her legs tightened around his waist, her nails biting harder into his skin to the point that blood ran in thin rivulets down his back, and she bit into his shoulder to muffle her cries of excitement. “Oh, you’re a wildcat, aintcha?” he growled, pressing her harder against the wall, his hips pistoning at an agonizingly slow pace.

“You have no idea,” she panted, sliding her hand back up his back to pull his head down for a hard, heated kiss as she began to roll her hips against, trying to encourage him to move faster. 

“You’re so tight,” he groaned, following her cues and thrusting faster as his control began to slip with each moan that slipped past her lips, “I’m not gonna last much longer.”

She crossed her ankles against the small of his back, tightening her hold on him so he couldn’t pull out, “Do it! Do it inside!” 

“But-”

“It’s a safe day,” she gasped pleadingly, afraid his hesitation meant he wasn’t going to listen, “and I’m on the pill!” She pulled his head close again, thrusting her tongue into his mouth to wrestle with his, hoping the distraction would be enough.

Much to her delight, her plan worked. His resistance seemed to melt away as his tongue moved against hers and he thrust once, twice, thrice before burying himself fully inside her. They cried out in unison, their voices echoing loudly about the locker room as they climaxed together, his hot seed spilling into her and filling her womb. Her eyes rolled back into her head and her body trembled as the heat spread throughout her body until the only thing holding her upright was his body pinning her against the wall.

They stayed like that until they both had caught their breath and her trembling had subsided before she loosened her death grip on him and he carefully set her down on her feet, holding onto her until she nodded that she was fine. She looked up at him, smiling at the already spreading pleasant soreness she always felt after great sex, but frowned when she noticed he was shivering, “You okay?”

Larry cleared his throat and nodded, rubbing his arms, “Yeah, it’s just about halfway through… the hot water started turning cold.”

Sandy snorted and turned off the water for him as they gathered his things and headed back into the main locker room to dry off and collect her clothes, chatting away amicably about plans for their upcoming date.


End file.
